As you all probably know, this year DEFCON CTF Final was completely in IPv6. There were 12 teams with IPv6 addresses of servers from dc19:c7f:2011:1::2 to dc19:c7f:2011:c::2.
You probably want to know what did it mean to the team #10 (sutegoma2) with IPv6 address dc19:c7f:2011:a::2?
For them it was extremely difficult to write connect-back shellcodes: it always contained \x0a string from the IP-address which is the caret sign "\n", so the shellcode got cut off by this character.
ddtek made some kind of IP-address team discrimination :-). Hopefully, they are not racists.
Moral: don't use connect-back shellcodes, get whatever you want and terminate inside one connection.
no problem to encode your IP in shellcode :)